The advantages of thermochemical processing of renewable organic feedstock for production of synthetic biofuels are noted. Chemical kinetic, thermodynamic, and thermophysical factors limiting the gasification rate of plant biomass and; therefore, the reactor throughput, are analyzed using wood cellulose as an example. It is shown that the very low thermal conductivity of polymeric materials is the main factor limiting the throughput of a volume-type thermochemical reactor. The processing advantages of gasifying a thin layer of organic matter heated by direct thermal contact with the working surfaces are theoretically justified using a one-dimensional model.